HEALTH UPDATEHealth is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
 World Health Organization

Vaccines: Protect Yourself and Those Around YouWorld Health Organization: “Immunization is a proven tool for controlling and even eradicating disease.”

by Joseph P. Demers
Guyana Journal, October 2009

How it works

Vaccines, or immunizations, are powerful weapons that modern medical practice has used to stop the spread of infectious disease throughout the world. Vaccines are effective against some viral and bacterial infections, and each vaccine is specific for a certain infection or group of infections. It is important to know that the vaccine itself isn't what fights off the infection; it simply aids your immune system in fighting the infection - a fight it might otherwise lose, depending on many different circumstances.

Unlike many of the medications taken in response to a condition or infection after it is diagnosed by a doctor, vaccines are unique in that they are given before you ever become sick with the disease. Instead, vaccines work by exposing your immune system to the disease before you acquire it from another source, so that if the actual viruses or bacteria infect your body, this will be remembered by the body's B-lymphocytes or B-cells. These cells in the body produce defenses against foreign viruses or bacteria in the body.

Essentially, it is a race between the B-cells and the virus to increase their numbers as fast as possible. After the virus is detected, the immune system produces more white blood cells, such as B-cells, that will then produce antibodies. Antibodies are a type of molecule made for the sole purpose of binding to antigens, or foreign material, as a way of signaling them to be destroyed by other white blood cells. If your white blood cells can identify the virus by the antibodies, they can quickly halt the infection before it becomes out of control.

Types of vaccines

Vaccines can be made from either dead or living antigens. Depending on which method is used, the vaccine is called killed, inactivated, or live attenuated. A killed vaccine is made from an antigen that is intact but dead. An inactivated antigen provides immunity against a toxin produced by bacteria, which is inactivated for use as a vaccine. Live attenuated vaccines are living antigens that have been weakened to the point that they are no longer dangerous to healthy individuals.

Generally, live attenuated vaccines create a longer lasting immunity; however, not all viruses are suitable to be developed as live vaccines. As well, some patients with compromised immune systems (children, the elderly, pregnant women, patients with chronic diseases, or those on medication that suppresses the immune system) should not get live vaccines because they are at risk for developing the full blown infection. “Booster shots” are given when an inactivated vaccination begins to wear off and the patient needs to re-establish their immunity.

A worldwide success story

The best examples of the benefit of vaccinating are the diseases that have been eliminated (eradicated) or significantly reduced around the world. Smallpox, a deadly virus that killed every fourth victim, had been spreading uncontrollably for thousands of years and was responsible for 300-500 million deaths in the 20th century alone. In 1967, an international vaccination campaign launched by the World Health Organization virtually eliminated the natural occurrence of this disease in 10 years. The polio virus is currently 99% eradicated worldwide, and comparable progress is being made against measles, tetanus and many other vaccine preventable diseases.

Myths and facts

Many common misconceptions about vaccines cause people to refuse them or choose not to have their children vaccinated. Unnecessary pain and suffering can be avoided by resolving some of these concerns:

Myth:

Don't vaccines have serious side effects that could cause more harm than good

Fact:

Nearly every vaccine has the potential to cause side effects; however, the majority of side effects are mild pain, redness, or tenderness at the injection site.

Rarely, serious side effects do occur in some patients. These incidents, however isolated they may be, are paid more attention to by patients, and often little or no mention is made of the benefits of vaccines. Thousands of people avoid deadly infection by receiving the recommended vaccinations for diseases such as the pneumococcus bacteria, hepatitis B-virus, tetanus, pertussis, haemophilus influenza B, and many others. In any treatment you are looking to receive, it is important to weigh the potential good and potential bad outcomes to decide what choice is best. When you compare the risks of infection versus the risks of complicated side effects for these vaccines, the benefits outweigh the risks that are possible in most cases. For example, hepatitis B can be easily contracted by casual contact, and with a high infant infection rate (90%) and very low (1 in 600,000) complication rate, it is important that infants receive this vaccine.

The exceptions to the general benefit vs. risk of vaccines are usually those with weakened immune systems, the child-bearing, or those allergic to any components of the vaccine. For this reason, it is important to keep a record of your known allergies, previous vaccines (and your experience with them), and any current medical conditions you may have.

Myth:

Giving someone vaccines for multiple diseases at once can be dangerous and increases the risk of becoming infected.

Fact:

The human body is a remarkable system, but the only reason we've been able to succeed as a species is because of our immune systems, which when working properly, defend us from hundreds of viral, bacterial, fungal, and parasitic invaders each day. If the body's immune system could not deal with the handful of vaccines routinely administered to children, we would not last very long after birth. The moment we are introduced into the world, our skin, nose and mouth become introduced to bacteria from our mother and our surroundings. Our ability to survive is dependent on being able to produce an immune response to these organisms so they don't grow uncontrollably. In addition, the naturally occurring infections are much different than the weakened or destroyed organisms in the vaccines that will only replicate about 20 times before dying.

Myth:

It's better to be naturally infected rather than immunized; immunizing weakens the immune system.

Fact:

Naturally becoming immune typically yields better immunity than does vaccine-induced immunity. Whereas a natural immunity is lifelong, artificial immunity may only last over several years. However, natural immunity does not occur unless one is infected with a wild, living microorganism and often there are damaging side effects, and sometimes death, after severe infection. The artificial alternative offers a high degree of safety with a minimal inconvenience of simply visiting the doctor's office on multiple occasions.

Myth:

Vaccines cause autism.

Fact:

Autism is a developmental impairment, affecting the social behavior and communication of those it affects. Autism begins in children before the age of three as signs of the disorder become more apparent. This also happens to be around the time when childhood vaccinations are administered, but it is important to realize that because two events occur together, it does not mean that one has caused the other.

Myth:

Vaccines contain mercury that can be harmful to children.

Fact:

The substance in question is known as thimerosal, an organic mercury compound that acts as a preservative in some vaccines. Preservatives are necessary in medications to prevent the growth of bacteria and other contaminants, but there is controversy surrounding the use of thimerosal in vaccines because of the toxic properties of mercury.

The fact is that mercury in the form that pollutes the environment is methylmercury, not ethylmercury as is used in thimerosal. Ethylmercury is eliminated from the body faster than methylmercury, and would therefore be less damaging to the kidneys and nervous system. Nevertheless, in 2001 the levels of mercury in thimerosal-containing vaccines was evaluated by the Food and Drug Administration, and determined it to be close to the Environmental Protection Agency's limit for amount of mercury people can be exposed to. In response to this finding, mercury-containing preservatives were removed from Hib, DTaP, and hepatitis B vaccines in the United States. The levels of mercury in vaccines have never been shown to cause kidney or neurologic problems in infants.

Immunization schedules

The CDC has the 2009 recommended immunization schedules for children, adolescents, and adults available online at http://www.cdc.gov/vaccines/recs/schedules/default.htm. Tools ranging from the “Catchup Scheduler,” vaccine screening forms, and blank vaccine record forms can help you stay aware and up to date with the vaccines recommended for you and your family members.

Traveler's immunizations

When traveling abroad, it is important to keep in mind that different countries have different standards of public health, and therefore diseases that are not common in the United States may be more common elsewhere. Based on the country you are traveling to, the Centers for Disease Control and Prevention (CDC) has provided a guide to ensure that you can seek the proper vaccinations for you and your family prior to traveling. It is recommended that you see a health-care provider at least 4-6 weeks before traveling in order to receive the most benefit from the vaccine.

To see what vaccinations are recommended for travel destinations around the world, please visit